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У статті надано клініко-інструментальний аналіз впливу препарату Білобіл інтенс на функціональний стан центральної нервової системи у хворих похилого віку, які перенесли ішемічний інсульт (у ранній відновний період). Відзначається позитивний вплив препарату на загальний стан хворих, когнітивні функції, неврологічний статус, якість життя, соціально-побутову адаптацію, також відбувається гармонізація структури біоелектричної активності головного мозку і поліпшення церебральної гемодинаміки, що дає авторам підставу рекомендувати включення препарату Білобіл інтенс до системи комплексної медикаментозної реабілітації хворих, які перенесли ішемічний інсульт.

У статті проаналізовано вплив базисної фармакотерапії на стан екстра- та інтракраніальної церебральної гемодинаміки у хворих на бронхіальну астму (БА) дітей. Монотерапія антилейкотрієновими препаратами нормалізує найбільшу кількість показників церебральної гемодинаміки, на другому місці — комбіноване лікування глюкокортикостероїдами та антилейкотрієновими препаратами, найменш ефективна базисна інгаляційна глюкокортикостероїдна терапія. Жодна проаналізована схема не усуває явища гіпоперфузії у вертебробазилярній зоні у хворих на БА дітей. У період ремісії декілька показників церебральної гемодинаміки, щодо яких усі перелічені схеми базисної фармакотерапії БА були ефективними, погіршилися та статистично не відрізнялись від аналогічних показників хворих із неконтрольованим перебігом БА. Хворі на БА діти повинні перебувати під наглядом дитячого невролога та потребують планового допплерографічного дослідження магістральних судин голови та шиї незалежно від ступеня контролю основного захворювання.

Background. The main risk factors for cardiovascular diseases (CVD) are diabetes mellitus, anemia, microalbuminuria, proteinuria, azotemia, hyperlipidemia, obesity, smoking, lack of physical activity, and non-traditional factors are metabolic and hemodynamic disorders. The combined effect of diabetes mellitus and renal insufficiency increases the risk of CVD and confirms the worse survival prognosis of these patients compared to the general population. The study was aimed to study changes in the parameters of cerebral hemodynamics in patients with type 2 diabetes mellitus receiving programmed hemodialysis. Materials and me­thods. During the period from January 1, 2019 to June 1, 2021, 117 patients suffering from type 2 diabetes mellitus with chronic renal failure stage V on programmed hemodialysis were examined and observed. Of these, there were 58 women and 59 men. The average age of men was 67.0 ± 4.2 years, women — 64.0 ± 5.6 years. Twenty patients of the matched age formed the control group. The number of hemodialysis sessions in patients ranged from 2 to 162. All patients underwent examinations that included general clinical, biochemical, hormonal blood tests, Dopplerography of the main arteries of the head. Results. With the increasing degree of cerebral ischemia, the linear velocity of blood flow (LBFV) decreased in all the main arteries of the head: the common caro­tid artery, the internal carotid artery, the vertebral artery on both sides (p < 0.05). At the same time, the differences in the LBFV from healthy individuals were significant. The stenosis of the lumen of the main vessels of the head occurred mostly in patients of the third group with stage V diabetic nephropathy and grade III chronic cerebral ischemia, while they most often had multiple vascular stenosis. Conclusions. Dopplerography of the main arteries of the head is an informative method for determining the prognosis of cerebral ischemia in patients with type 2 diabetes mellitus and chronic kidney disease. Linear blood flow velocity was reduced in all groups of patients with type 2 diabetes mellitus and chronic kidney disease., Актуальність. Головними факторами ризику серцево-судинних захворювань (ССЗ) є цукровий діабет, анемія, мікроальбумінурія, протеїнурія, азотемія, гіперліпідемія, ожиріння, куріння, відсутність фізичної активності, а нетрадиційними факторами — метаболічні та гемодинамічні порушення. Одночасний вплив цукрового діабету і ниркової недостатності збільшує ризик ССЗ і підтверджує незадовільний прогноз виживання цих пацієнтів порівняно з населенням у цілому. Мета дослідження — вивчити зміни параметрів церебральної гемодинаміки у хворих на цукровий діабет 2-го типу, які отримують програмний гемодіаліз. Матеріали та методи. За період з 1 січня 2019 по 1 червня 2021 р. оглянуто і обстежено 117 пацієнтів, які страждають на цукровий діабет 2-го типу з хронічною нирковою недостатністю V ст. на програмному гемодіалізі. З них жінок було 58, чоловіків — 59. Середній вік чоловіків становив 67,0 ± 4,2 року, жінок — 64,0 ± 5,6 року. 20 хворих відповідного віку становили групу контролю. Число сеансів гемодіалізу в пацієнтів становило від 2 до 162. Усім пацієнтам виконувалися дослідження, що включали загальноклінічні біохімічні, гормональні дослідження крові, допплерографію магістральних артерій голови. Результати. У міру зростання ступеня ішемії мозку зменшувалася лінійна швидкість кровотоку (ЛШК) у всіх магістральних артеріях голови: загальній сонній артерії, внутрішній сонній артерії, хребетній артерії з обох сторін (р < 0,05). При цьому відмінності в ЛШК від здорових осіб були вірогідними. Найчастіше стеноз просвіту магістральних судин голови траплявся у хворих третьої групи з діабетичною нефропатією V стадії і хронічною ішемією мозку III ступеня, при цьому в них найчастіше спостерігалося множинне стенозування судин. Висновки. Допплерографія магістральних артерій голови є інформативним методом для визначення прогнозу ішемії головного мозку в пацієнтів із цукровим діабетом 2-го типу з хронічною хворобою нирок. Лінійна швидкість кровотоку була зниженою в усіх групах хворих на цукровий діабет 2-го типу з хронічною хворобою нирок.

Sodium bicarbonate (NaHCOsub3/sub) is no longer recommended by the Neonatal Resuscitation Program (NRP), but is still being used by some neonatologists. The effects of NaHCOsub3/subon cerebral hemodynamics are unclear. Therefore, we investigated the effects of NaHCOsub3/subon cerebral blood flow (CBF) and cerebrovascular function using a newborn piglet model.Newborn pigs were anesthetized, intubated, and ventilated. Cranial windows were implanted to evaluate changes in pial arteriolar diameters (PADs) as a surrogate for CBF during a 4-h intravenous infusion of 3% NaHCOsub3/sub. Cerebrovascular reactivity to vasodilators and vasoconstrictors was investigated during vehicle control and during NaHCOsub3/subinfusion.NaHCOsub3/subinfusion caused significant and progressive pial arteriolar vasoconstrictions. During NaHCOsub3/subinfusion, cerebrovascular reactivity was preserved. Adding vasodilators decreased cerebral vasoconstriction, while adding vasoconstrictors exaggerated cerebral vasoconstriction.Intravenous infusion of NaHCOsub3/subover 4 h caused progressive vasoconstriction of pial arterioles. Cerebrovascular function evaluated by the responses of pial arterioles to physiologically relevant vasoconstrictors and vasodilators was preserved during NaHCOsub3/subinfusion. A notable additional reduction of PADs was observed during NaHCOsub3/subinfusion in the presence of vasoconstrictors. Extrapolating our findings to human neonates should alarm the clinicians that using NaHCOsub3/subin neonates may cause cerebral hypoperfusion.Cerebral vasoconstriction occurs during slow infusion of 3% diluted NaHCOsub3/sub. Cerebral vasoconstriction is exaggerated when another vasoconstrictor is added during NaHCOsub3/subinfusion. Cerebrovascular function is preserved during NaHCOsub3/subinfusion. Clinicians should be aware of the risk of cerebral hypoperfusion with NaHCOsub3/subinfusion in vulnerable neonates.

Despite providing cerebral tissue oxygen saturation (StOTo investigate if the additional monitoring of cerebral blood volume by TD-NIRS facilitates the understanding of cerebral hemodynamic conditions in patients with congenital heart disease.Preoperative TD-NIRS values were retrospectively reviewed in patients who underwent a cardiac surgery or catheter examination. We compared the values between patients with single and two ventricles. Moreover, we investigated the association of these values with the demographic and clinical variables.There was no significant difference in StO2 between single ventricle and two ventricles groups (median: 59.9 vs. 54.4, median difference [95% CI]: -4.06 [-9.90 to 2.90], p = .37). However, cerebral blood volume was significantly higher in the single ventricle group (median: 4.68 vs. 2.84, median difference [95% CI]: -2.01 [-2.88 to -1.06], p .001). Spearman's rank correlation analysis demonstrated an association between StO2 and postmenstrual age (r = 0.35, p = .03). In contrast, cerebral blood volume was correlated with single ventricle physiology (r = 0.62, p .001), postmenstrual age (r = 0.74, p .001), central venous pressure (r = 0.38, p = .02), and SaO2 (r = -0.38, p = .02). The multivariable regression analysis identified the postmenstrual age, single ventricle physiology, and SaO2 as independent factors associated with cerebral blood volume. In the logistic analysis, cerebral blood volume was identified as a significant predictor of unfavorable conditions.Cerebral blood volume monitoring detected differences in cerebral hemodynamic conditions, related to the age and the type of ventricle physiologies. However, the differences were not apparent in StO

After revascularization surgery for patients with moyamoya disease (MMD), local and global hemodynamic changes occur intraoperatively and in the early postoperative period. Local cerebral hyperperfusion and watershed shift ischemia are well-known perioperative pathologies after revascularization for MMD, but early venous filling phenomenon is markedly rare. We report the case of a 19-year-old woman with hemorrhagic-onset MMD who presented with grand mal seizure and subarachnoid hemorrhage. She underwent superficial temporal artery (STA)–middle cerebral artery (MCA) anastomosis combined with indirect pial synangiosis on the affected hemisphere. Intraoperatively, notable early arterial blood filling in the fine cortical vein was observed around the site of anastomosis right after the STA–MCA anastomosis under the surgical microscope and fluorescence indocyanine green video angiography. Recovery of consciousness after general anesthesia was normal, although she exhibited a focal seizure 1 hour later. Postoperative magnetic resonance imaging was not remarkable, and cerebral hemodynamics significantly improved in the acute stage after surgical revascularization. Considering the intrinsic vulnerability of the microvascular anatomy of MMD, the present case is notable because early venous filling was observed intraoperatively. This phenomenon suggests the existence of a potential arteriovenous shunt as an underlying pathology of MMD, but its implications in the early postoperative course should be further verified in a larger number of MMD patients undergoing surgical revascularization.

BACKGROUND: Aerobatic pilots must withstand high and sudden acceleration forces (Gz) up to 10 Gz. The physiological consequences of such a succession of high and abrupt positive and negative Gz on the human body over time remain mostly unknown. This case report emphasizes changes in physiological factors such as cerebral oxygenation and heart rate dynamics collected in real aerobatic flights.CASE REPORT: A 37-yr-old man, experienced in aerobatic flying, voluntarily took part in this study. During two flight runs (15-20 min), the pilot performed aerobatic maneuvers with multiple high (10 Gz) positive and negative accelerations. During the flights he wore a Polar heart rate sensor while cerebral oxygenation was measured continuously over his prefrontal cortex via near-infrared spectroscopy (NIRS). NIRS allows for measurement of the relative concentration changes of oxygenated hemoglobin (O2Hb) and deoxygenated hemoglobin (HHb), making it possible to determine cerebral oxygenation and hemodynamic status.DISCUSSION: The continuous in-flight monitoring of O2Hb and HHb revealed the large effects of successive positive and negative Gz exposures on cerebral hemodynamics alterations. The results showed a significant and positive correlation between changes in Gz exposures and O2Hb concentration. This case report highlights that NIRS provides some valuable and sensitive indicators for the monitoring of cerebral hemodynamics during aerobatic flights exposed to multiple and high acceleration forces. To our knowledge, this first study quantifying cerebral oxygenation changes in aerobatics opens the way for the assessment of individual physiological responses and tolerance in pilots to repeated high Gz during real flights.Fresnel E, Dray G, Pla S, Jean P, Belda G, Perrey S. Cerebral oxygenation responses to aerobatic flight. Aerosp Med Hum Perform. 2021; 92(10):838-842.

Актуальність. Огляд вітчизняної та зарубіжної науково-дослідної літератури свідчить, що на сьогодні системні наукові дослідження щодо взаємозв’язку між рівнем нейропептиду VIP (вазоактивний інтестинальний пептид — vasoactive intestinal peptide) та інтерлейкіну-5 у сироватці крові та станом мозкової гемодинаміки у хворих на бронхіальну астму дітей відсутні. Метою дослідження було встановити можливі впливи нейропептиду VIP та інтерлейкіну-5 на показники екстракраніальної гемодинаміки у хворих на бронхіальну астму дітей, проаналізувати гендерні особливості цих показників. Матеріали та методи. Проведено імунологічне дослідження сироватки крові для визначення рівня нейропептиду VIP та інтерлейкіну-5 у 54 хворих на бронхіальну астму дітей, серед яких були 21 дівчинка та 33 хлопчики віком 10–17 років. Контрольну групу становили 20 здорових дітей, які були ідентичні хворим за гендерним та віковим складом. Діти були обстежені двічі — при неконтрольованому та контрольованому перебігу хвороби. Також усім дітям проведено ультразвукове допплерографічне дослідження магістральних судин голови та шиї. Результати. Аналіз рівнів нейропептиду VIP та інтерлейкіну-5 установив гендерну залежність їх коливань: рівень нейропептиду VIP був статистично нижчим, а інтерлейкіну-5 — вищим у хворих хлопчиків із неконтрольованим перебігом бронхіальної астми порівняно із здоровими хлопчиками. У хворих із контрольованим перебігом бронхіальної астми негативний вплив на показники екстракраніальної гемодинаміки є мінімальним як у дівчаток, так й у хлопчиків. Висновки. Для здійснення дієвого контролю над перебігом захворювання потрібно враховувати зміни показників екстракраніальної гемодинаміки у хворих на бронхіальну астму дітей залежно від їх статі, що дозволить уникнути цереброваскулярних ускладнень у даного контингенту хворих.

Актуальність. Дані щодо кількості хворих із хронічною ішемією головного мозку серед дітей та підлітків поодинокі й нечисленні. Отже, актуальність дослідження стану та змін мозкової гемодинаміки, зокрема венозної циркуляції, у дітей, хворих на бронхіальну астму, не викликає сумніву й є вкрай гострим питанням. Мета. Вивчення особливостeй стану венозної гемодинаміки головного мозку у дітей, хворих на бронхіальнy астмy. Матеріали та методи. Проведено ультразвукове допплерографічне дослідження 101 хворих на бронхіальну астму та 30 здорових дітей віком 10–17 років. Хворих дітей було розподілено за гендерною приналежністю, ступенем контролю та тривалістю захворювання. Ультразвукова допплерографія здійснювалась з визначенням максимальної лінійної швидкості кровоплину в руслі базальної вени Розенталя. Результати. Встановлено явища персистуючої венозної дисгемії та веностазу у хворих дітей, особливо хлопчиків, незалежно від ступеня контролю бронхіальної астми. На показники венозної гемодинаміки також негативно впливала тривалість захворювання понад 5 років. Висновки. Oсобливості венозної циркуляції y дітей, хворих на бронхіальнy астмy, є ранніми доклінічними ознакaми цереброваскулярних порушень. Запропоновано віднести їх до групи ризику щодо виникнення цереброваскулярної патології в майбутньому. Доцільно доповнити диспансернe спостереження дітей, хворих на бронхіальнy астмy, дослідженням стану венозної гемодинаміки з використанням транскраніальної допплерографії та дуплексного сканування магістральних судин головного мозку, що забезпечить ранню діагностику цереброваскулярних порушень.

To analyze the brain CT imaging data of children with cerebral palsy (CP), deep learning-based electronic computed tomography (CT) imaging information characteristics were used, thereby providing help for the rehabilitation analysis of children with CP and comorbid epilepsy. The brain CT imaging data of 73 children with CP were collected, who were outpatients or inpatients in our hospital. The images were randomly divided into two groups. One group was the artificial intelligence image group, and hybrid segmentation network (HSN) model was employed to analyze brain images to help the treatment. The other group was the control group, and original images were used to help diagnosis and treatment. The deep learning-based HSN was used to segment the CT image of the head of patients and was compared with other CNN methods. It was found that HSN had the highest Dice score (DSC) among all models. After treatment, six cases in the artificial intelligence image group returned to normal (20.7%), and the artificial intelligence image group was significantly higher than the control group (X2 = 335191, P < 0.001 ). The cerebral hemodynamic changes were obviously different in the two groups of children before and after treatment. The VP of the cerebral artery in the child was (139.68 ± 15.66) cm/s after treatment, which was significantly faster than (131.84 ± 15.93) cm/s before treatment, P < 0.05 . To sum up, the deep learning model can effectively segment the CP area, which can measure and assist the diagnosis of future clinical cases of children with CP. It can also improve medical efficiency and accurately identify the patient’s focus area, which had great application potential in helping to identify the rehabilitation training results of children with CP.

Ketamine has a number of clinical uses and properties that suggest a role for the drug in neuroanestheisa practice. “Dogma” and “myths” persist with regard to its effects on cerebral hemodynamics and intracranial pressure which have limited its use in Neuroanesthesia and care of the critically ill brain-injured patient. This review aims to educate the clinician on the possible role of ketamine in modern neuroanesthesia practice. A number of systemic reviews support the use of ketamine in patients with acute brain injury and raised intracranial pressure (ICP). Pre-clinical work suggests that ketamine may have mechanisms of action compatible with neuroprotection including modifying glutamate excitatory-driven mechanisms of brain injury. There is emerging clinical evidence to suggest that ketamine may inhibit spreading depolarizations (SDs), a cortical electrical phenomenon associated with brain injury. Ketamine is no longer contraindicated in the care of the brain-injured patient, and its properties of potent analgesia, dissociative anesthesia, and minimal effects on both the hemodynamic and respiratory system are being utilized in the pre-hospital and emergency room setting. Good grade data on meaningful clinical outcomes is presently lacking to support the use of ketamine as a drug with neuroprotection properties but is an area of ongoing interest.

The cerebrovascular effects of supine hypertension (SH) are still poorly understood. With aging and atherosclerosis of the vascular system, it is not uncommon for SH and non-neurogenic orthostatic hypotension to co-occur. Given evidence for end organ damage and more extreme cerebral dysfunction in those with SH-orthostatic hypotension, we hypothesized that SH would be associated with impaired cerebral autoregulation. The aim of this study was to characterize the cerebrovascular response to orthostasis. Near-infrared spectroscopy was used to quantify the cerebrovascular response. We analyzed data from Wave 3 of TILDA (The Irish Longitudinal Study on Ageing; n=2750). Cerebral oxygenation and blood pressure (BP) were monitored continuously during an active stand. Responses were modeled using multilevel mixed-effects models and adjusted for important covariates such as age, sex, education, antihypertensive medications, and comorbidities. Forty-nine percent of the sample had SH. Those with SH demonstrated an impaired BP response and a slower recovery of BP after standing, graded by severity of SH. The cerebral oxygenation response was similar for both groups, but when standardized to mean arterial BP, the response was impaired in those with SH. A deficit of −0.83% (95% CI, −0.93 to −0.74) remained after 3 minutes of standing. Our study determined that cerebral oxygenation and cerebral autoregulation are impaired in those with SH. In older patients, consideration should be given to measuring SH and screening for orthostatic hypotension. Therapeutic studies are needed to better understand the relationship between cerebral oxygenation, medications, supine BP, and orthostatic hypotension.

Accumulating evidence suggests vascular dysregulation in preclinical Alzheimer’s disease. In this study, cerebral hemodynamics and their coupling with cognition in middle-aged apolipoprotein ε4 carriers (APOEε4+) were investigated. Longitudinal 3 T T1-weighted and arterial spin labelling MRI data from 158 participants (40–59 years old) in the PREVENT-Dementia study were analysed (125 two-year follow-up). Cognition was evaluated using the COGNITO battery. Cerebral blood flow (CBF) and cerebrovascular resistance index (CVRi) were quantified for the flow territories of the anterior, middle and posterior cerebral arteries. CBF was corrected for underlying atrophy and individual hematocrit. Hemodynamic measures were the dependent variables in linear regression models, with age, sex, years of education and APOEε4 carriership as predictors. Further analyses were conducted with cognitive outcomes as dependent variables, using the same model as before with additional APOEε4 × hemodynamics interactions. At baseline, APOEε4+ showed increased CBF and decreased CVRi compared to non-carriers in the anterior and middle cerebral arteries, suggestive of potential vasodilation. Hemodynamic changes were similar between groups. Interaction analysis revealed positive associations between CBF changes and performance changes in delayed recall (for APOEε4 non-carriers) and verbal fluency (for APOEε4 carriers) cognitive tests. These observations are consistent with neurovascular dysregulation in middle-aged APOEε4+.

Diminished cerebrovascular function is associated with reduced cognitive ability. Habitual exercise may maintain or improve cerebrovascular function; however, limited information exists regarding the optimal exercise prescription for cerebrovascular health. Although aerobic exercise is associated with improved systemic vascular function, the influence of resistance exercise on vascular health is unclear. Therefore, the purpose of this study was to examine the influence of habitual exercise training on cerebrovascular function in healthy young adults. We evaluated 13 untrained (age = 27 ± 5 yr; 11 men, 2 women), 13 aerobic-trained (age = 28 ± 5 yr; 10 men, 3 women), and 13 resistance-trained (age = 24 ± 4 yr; 11 men, 2 women) adults. Middle cerebral artery velocity (MCAv), mean arterial pressure (MAP), and end-tidal carbon dioxide were continuously measured at rest and in response to hypercapnia. At rest, there were no differences between groups for MCAv, however, resistance-trained adults had greater cerebrovascular conductance compared with aerobic-trained adults (0.79 ± 0.26 cm/s/mmHg vs. 0.56 ± 0.17 cm/s/mmHg; P < 0.05). In response to hypercapnia, cerebrovascular reactivity and MAP reactivity were not different between groups. There was no association between aerobic fitness or measures of exercise volume and any variable of cerebrovascular function in the combined or individual groups. Our results suggest that the mode of exercise training does not impact cerebrovascular reactivity in healthy young adults, however, it may influence resting cerebral hemodynamics. Future research could examine the influence of habitual exercise training on cerebrovascular function with aging. NEW & NOTEWORTHY Habitual exercise may influence cerebral hemodynamics, as it affects other variables of vascular health in this population. We report that habitual exercise training does not influence cerebrovascular reactivity in young adults, as there were no significant differences between aerobic-trained, resistance-trained, and untrained individuals. Despite this finding, the mode of habitual exercise training had a moderate influence on resting cerebral hemodynamics such that resistance-trained adults had greater cerebrovascular conductance compared with aerobic-trained adults.

Objective Multiple factors have been identified as causes of intracranial compliance impairment (ICCI) among patients with obesity. On the other hand, obesity has been linked with worst outcomes in COVID‐19. Thus, the hypothesis of severe acute respiratory syndrome (SARS) conducing to cerebral hemodynamic disorders (CHD) able to worsen ICCI and play an additional role on prognosis determination for COVID‐19 among obese patients becomes suitable. Methods 50 cases of SARS by COVID‐19 were evaluated, for the presence of ICCI and cerebrovascular circulatory disturbances in correspondence with whether unfavorable outcomes (death or impossibility for mechanical ventilation weaning [MVW]) within 7 days after evaluation. The objective was to observe whether obese patients (BMI ≥ 30) disclosed worse outcomes and tests results compared with lean subjects with same clinical background. Results 23 (46%) patients among 50 had obesity. ICCI was verified in 18 (78%) obese, whereas in 13 (48%) of 27 non‐obese (p = 0,029). CHD were not significantly different between groups, despite being high prevalent in both. 69% unfavorable outcomes were observed among obese and 44% for lean subjects (p = 0,075). Conclusion In the present study, intracranial compliance impairment was significantly more observed among obese subjects and may have contributed for SARS COVID‐19 worsen prognosis.

Background: Increasing interest in identifying of cerebral hemodynamics alterations as cause of possible onset or worsening of cognitive impairment in elderly patients with vascular risk factors. Introduction: Intracranial ultrasound is a non-invasive, repeatable inexpensive method for recording variation of the cerebral vascular tree in physiological and pathological conditions as well in the diagnosis of vascular dementia (VaD). Methods: PubMed, Embase, Cochrane library and reference lists have been searched for articles published until March 30, 2020. Results: Clinical studies reported different Transcranial Doppler (TCD) parameters and subsequently transcranial duplex with color code (TCCD) in patients affected by vascular dementia. The number of studies using TCCD remains limited and most of available data are still based on TCD. However, the use of transcranial Doppler could better stratify elderly patients with initial signs of cognitive impairment. Conclusion: Intracranial ultrasound employment to detect cerebral hemodynamic changes in VaD patients has been briefly discussed in this review.

BACKGROUND Disruption of brain oxygen delivery and consumption after hypoxic-ischemic injury contributes to neonatal mortality and neurological impairment. Measuring cerebral hemodynamic parameters, including cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2 ), is clinically important. PURPOSE Phase-contrast (PC), velocity-selective arterial spin labeling (VSASL), and T2 -relaxation-under-phase-contrast (TRUPC) are magnetic resonance imaging (MRI) techniques that have shown promising results in assessing cerebral hemodynamics in humans. We aimed to test their feasibility in quantifying CBF, OEF, and CMRO2 in piglets. STUDY TYPE Prospective. ANIMAL MODEL Ten neonatal piglets subacutely recovered from global hypoxia-ischemia (N = 2), excitotoxic brain injury (N = 6), or sham procedure (N = 2). FIELD STRENGTH/SEQUENCE VSASL, TRUPC, and PC MRI acquired at 3.0 T. ASSESSMENT Regional CBF was measured by VSASL. Global CBF was quantified by both PC and VSASL. TRUPC assessed OEF at the superior sagittal sinus (SSS) and internal cerebral veins (ICVs). CMRO2 was calculated from global CBF and SSS-derived OEF. End-tidal carbon dioxide (EtCO2 ) levels of the piglets were also measured. Brain damage was assessed in tissue sections postmortem by counting damaged neurons. STATISTICAL TESTS Spearman correlations were performed to evaluate associations among CBF (by PC or VSASL), OEF, CMRO2 , EtCO2 , and the pathological neuron counts. Paired t-test was used to compare OEF at SSS with OEF at ICV. RESULTS Global CBF was 32.1 ± 14.9 mL/100 g/minute and 30.9 ± 8.3 mL/100 g/minute for PC and VSASL, respectively, showing a significant correlation (r = 0.82, P

This study aimed to investigate the effects of alteplase on patient neurological function and serum levels of stromal cell-derived factor-1 (SDF-1), claudin-5, neuron-specific enolase (NSE), coagul...

The recommendations of international guidelines for the management of asymptomatic carotid stenosis (ACS) often vary considerably and extend from a conservative approach with risk factor modification and best medical treatment (BMT) alone, to a more aggressive approach with a carotid intervention plus BMT. The aim of the current multispecialty position statement was to reconcile the conflicting views on the topic. A literature review was performed with a focus on data from recent studies. Several clinical and imaging high-risk features have been identified that are associated with an increased long-term ipsilateral ischemic stroke risk in patients with ACS. Such high-risk clinical/imaging features include intraplaque hemorrhage, impaired cerebrovascular reserve, carotid plaque echolucency/ulceration/ neovascularization, a lipid-rich necrotic core, a thin or ruptured fibrous cap, silent brain infarction, a contralateral transient ischemic attack/stroke episode, male patients

Aims Randomized trials support the safety and efficacy of direct oral anticoagulants (DOACs) vs. vitamin K antagonists (VKA) in patients with nonvalvular atrial fibrillation (AF), leading to increased use of these compounds. Crushed forms of DOACs have shown to be reliable, but evidence supporting percutaneous endoscopic gastrostomy (PEG) delivery is lacking. PEG is a long-term option for enteral food and drug delivery in patients unable to maintain oral intake, bypassing the risks and disadvantages of parenteral nutrition. We investigate the safety and efficacy of Edoxaban administered via PEG in patients with atrial fibrillation and a clinical indication for a long-term anticoagulation. Methods and results In this prospective, single centre observational study, 12 PEG-treated patients with indication to anticoagulation will receive edoxaban via PEG and will be followed-up to 6 months. Plasma anti-Factor Xa activity and edoxaban concentrations will be assessed. Thromboembolic (ischaemic stroke, systemic embolism, venous thromboembolism) and bleeding events (Bleeding Academic Research Consortium and Thrombolysis in Myocardial Infarction) will be recorded at 1 and 6 months. A retrospective analysis of 5 AF cases undergoing PEG-implantation at our Institution, who received edoxaban via PEG, showed plasma anti-FXa levels at steady state of 146 ± 15 ng/ml, without major adverse event at a mean follow-up of 6 months. Conclusion We prospectively investigate PEG-administration of edoxaban in PEG-treated patients requiring long term anticoagulation. Our preliminary retrospective data support this route of DOAC administration.

The growing epidemiological burden of atrial fibrillation (AF) warrants urgent clarification of the mechanisms at the basis of the independent association between the arrhythmia and cognitive decline/dementia. Several mechanisms have been proposed, such as silent cerebral lesions (subclinical ischemia or micro-haemorrages), a chronic reduction in mean cerebral blood flow, AF-associated pro-inflammatory status and cerebral endothelial dysfunction. However, a new hypothesis based on computational da-ta has recently emerged, which claims that AF irregular rhythm itself may promote direct deleterious beat-to-beat effects, which translates into critical hemodynamic events in the distal cerebral circle. To overcome the limitations of the currently adopted techniques in the study of cerebral circle (transcranial Doppler and Arterial Spin Labeling MRI), we recently demonstrated that cerebral near-infrared spectroscopy (NIRS) with high sampling frequency (20 Hz) may provide beat-to-beat hemodynamic in-sights from the cerebral microcirculation, paving the way for the assessment of distal cerebral hemodynamics during AF. Should the computational findings be confirmed, it will be fundamental to evaluate whether the most aggressive rhythm control strate-gies (such as transcatether ablation) may contribute to reduce cognitive burden in AF patients.

Objective ‒ to determine the features of the functioning of the circulatory system in patients with arteriovenous malformations (AVM) of the brain after endovascular operations with long-term observation.Materials and methods. 479 patients with cerebral AVM were examined and treated, of which 377 (78.7 %) were men and 102 (21.3 %) were women. The average age of patients was (27.5±3.5) years. Patients aged 18‒30 years predominated (75.4 %). A dynamic observation of 347 patients after endovascular treatment after 3, 6, 12 and 24 months and more was carried out. Patients underwent cerebral angiography, computed tomography, magnetic resonance imaging, single-photon emission computed tomography, echocardiography, Doppler cardiography, electrocardiography, duplex scanning of cerebral vessels.Results. The study shows the effect of arteriovenous shunting on cerebral and systemic hemodynamics in general. Switching off AVM from the cerebral blood flow improved cerebral hemodynamics already in the early postoperative period, the changes were more significant after 3‒6 months of observation and in some cases reached values ​​in healthy individuals 2 years after the operation. In 52.8 % of patients with AVM, systemic circulation disorders occurred due to an increase in heart rate, minute and stroke blood volumes, left ventricular ejection fraction with an increase in mechanical load on the heart, which led to changes in systolic contraction and diastolic relaxation of the left ventricle of the heart with the development of heart failure. Switching off the AVM from the cerebral blood flow did not cause significant changes in heart functions in the early postoperative period; positive changes occurred over a long period. Dynamic observation showed a positive restructuring of the functioning of the circulatory system in patients after endovascular exclusion of the malformation.Conclusions. Arteriovenous malformations are hemodynamically active systems that lead to hemodynamic-perfusion changes, both at the local and at the general hemodynamic level. The exclusion of the malformation from the bloodstream contributes to the regression of disorders of cerebral and intracardiac blood flow caused by the anatomical and functional characteristics of the malformation itself and its clinical course.

Object of study:pregnancy in women with a history of cesarean section, perinatal period. The problem to be solved:clarification of the perinatal significance of the factor “scarred uterus”, substantiation of the clinical significance of the test with acoustic stimulation of the fetus as a method for predicting early neonatal adaptation. Main scientific results:it was found that pregnancy in women with a history of cesarean section is characterized by an increased perinatal risk and is associated with psychoemotional stress of the mother, which affects the reactivity of fetal cerebral hemodynamics. It has been shown that the test with acoustic stimulation of fetus allows one to gain an idea of the fetus's perception of stressful influences, which should be taken into account when drawing up a delivery plan. The area of practical use of research results:obstetric departments of maternity hospitals and multidisciplinary hospitals. An innovative technological product:technology for assessing the state of the fetus in full-term pregnancy, which allows predicting complications of early neonatal adaptation based on the susceptibility of the fetus in the test with acoustic stimulation. Scope of application of an innovative technological product:obstetric clinical practice, perinatal medicine.

Motor imagery is defined as an act wherein an individual contemplates a mental action of motor execution without apparent action. Mental practice executed by repetitive motor imagery can improve motor performance without simultaneous sensory input or overt output. We aimed to investigate cerebral hemodynamics during motor imagery and motor execution of a self-feeding activity using chopsticks. This study included 21 healthy right-handed volunteers. The self-feeding activity task comprised either motor imagery or motor execution of eating sliced cucumber pickles with chopsticks to examine eight regions of interest: pre-supplementary motor area, supplementary motor area, bilateral prefrontal cortex, premotor area, and sensorimotor cortex. The mean oxyhemoglobin levels were detected using near-infrared spectroscopy to reflect cerebral activation. The mean oxyhemoglobin levels during motor execution were significantly higher in the left sensorimotor cortex than in the supplementary motor area and the left premotor area. Moreover, significantly higher oxyhemoglobin levels were detected in the supplementary motor area and the left premotor area during motor imagery, compared to motor execution. Supplementary motor area and premotor area had important roles in the motor imagery of self-feeding activity. Moreover, the activation levels of the supplementary motor area and the premotor area during motor execution and motor imagery are likely affected by intentional cognitive processes. Levels of cerebral activation differed in some areas during motor execution and motor imagery of a self-feeding activity. This study was approved by the Ethical Review Committee of Nagasaki University (approval No. 18110801) on December 10, 2018., Neural Regeneration Research, 16(4), pp.778-782; 2020

This study evaluated intradialytic cerebral hemodynamics measured by transcranial Doppler (TCD) in intermittent hemodialysis (iHD) versus nightly peritoneal dialysis (NIPD). Intradialytic TCD was serially performed in chronic dialysis patients receiving iHD ( n = 10) and NIPD ( n = 10). A linear mixed model was used to model mean flow velocity (MFV), pulsatility index (PI), and mean arterial pressure (MAP) as functions of time and treatment group. Intradialytic cerebral volatility (IDCV) was calculated using the coefficient of variation (CV) and mean absolute value of change (AVC) of each patient’s MFV, PI, and MAP values over time. Mixed model analyses found no significant difference between MFV, PI, and MAP treatment groups in change over time, though volatility differed significantly. Mean CV values for MFV, PI, and MAP were higher in iHD than NIPD (MFV 0.22 vs. 0.10, p = 0.005; PI 0.14 vs. 0.08, p = 0.003; MAP 0.057 vs. 0.032, p = 0.009). AVC values were similarly higher in iHD compared to NIPD (MFV 8.26 vs. 4.43, p = 0.04; PI 0.17 vs. 0.084, p < 0.001; MAP 6.05 vs. 2.9, p = 0.003). PI, MFV, and MAP were more stable in NIPD than iHD, as measured by intradialytic TCD monitoring. This study identifies IDCV as a unique TCD metric for intradialytic cerebral hemodynamics.

Cerebral revascularization utilizing a variety of bypass techniques can provide either flow augmentation or flow replacement in the treatment of a range of intracranial pathologies, including moyamoya disease, intracranial atherosclerotic disease, and complex aneurysms that are not amenable to endovascular or simple surgical techniques. Though once routine, the publication of high-quality prospective evidence, along with the development of flow-diverting stents, has limited the indications for extracranial-to-intracranial (EC-IC) bypass. Nevertheless, advances in imaging, assessment of cerebral hemodynamics, and surgical technique have changed the risk-benefit calculus for EC-IC bypass. New variations of revascularization surgery involving multiple anastomoses, flow preserving solutions, IC-IC constructs, and posterior circulation bypasses have been pioneered for otherwise difficult to treat pathology including giant aneurysms, dolichoectasia, and medically refractory intracranial atherosclerosis. This review provides a practical update on recent advances in adult intracranial bypass surgery.

Purpose of review To provide an overview of acute and chronic repeated concussion. We address epidemiology, pathophysiology, anesthetic utilization, and provide some broad-based care recommendations. Recent findings Acute concussion is associated with altered cerebral hemodynamics. These aberrations can persist despite resolution of signs and symptoms. Multiple repeated concussions can cause chronic traumatic encephalopathy, a disorder associated with pathologic findings similar to some organic dementias. Anesthetic utilization is common following concussion, especially soon after injury, a time when the brain may be most vulnerable to secondary injury. Summary Brain physiology may be abnormal following concussion and these abnormalities may persist despite resolutions of clinical manifestations. Those with recent concussion or chronic repeated concussion may be susceptible to secondary injury in the perioperative period. Clinicians should suspect concussion in any patient with recent trauma and strive to maintain cerebral homeostasis in the perianesthetic period.

Background Neuromonitoring at the bedside is the key to understand the pathophysiological mechanisms of brain injury associated with neonatal encephalopathy. The current practice is to monitor the forehead using a noninvasive cerebral oximetry-it remains unknown to what extent cerebral hemodynamics in other brain regions is different to the frontal region. Method A multichannel near-infrared spectroscopy (NIRS) system was used to monitor neonates (n = 14) with fetal acidosis and mild neonatal encephalopathy at four brain regions (the frontal, posterior, left temporal, and right temporal lobes). The data were compared to delineate the regional difference in (1) cerebral hemodynamics and (2) pressure autoregulation. For both analyses, wavelet transform coherence was applied. Results We observed frontal-posterior heterogeneity as indicated by significantly lower coherence between these two regions (p = 0.02). Furthermore, areas with regional magnetic resonance imaging (MRI)-detected lesions showed greater hemodynamic variations compared to non-affected areas (p = 0.03), while cerebral autoregulation was not affected and showed no difference. Conclusion Cerebral hemodynamics in mild neonatal encephalopathy is heterogeneous across different brain regions, while cerebral autoregulation remains intact. These findings indicate the robustness of the wavelet measure of cerebral autoregulation in this population, but need to be further investigated in the presence of severe injury. Impact This proof-of-concept study is the first to investigate the regional difference of cerebral hemodynamics and autoregulation in mild neonatal encephalopathy. Study findings confirm that brain functions are complex in the developing neonatal brain and that cerebral hemodynamics are region specific in newborns with frontal-posterior heterogeneity among brain regions probed by multichannel NIRS. Regional MRI lesions were associated with differences across NIRS regional channels among the affected side. Cerebral autoregulation with multichannel NIRS is not affected by regional MRI abnormalities.

Introduction . Osteochondrosis of the cervical spine is a very common disease that causes a significant decrease in the quality of life of patients. In the case of pronounced changes in the cervical spine with osteochondrosis, there is a violation of blood circulation in the cerebral cortex, which leads to pronounced clinical symptoms. The aim of this study was to identify a correlation between bioelectrical activity and cerebral hemodynamics in patients with osteochondrosis of the cervical spine. Materials and methods . The examination involved 25 patients of the neurosurgical department who received conservative treatment for exacerbation of osteochondrosis of the cervical spine, and 25 volunteers without a history of diseases of the spine and joints. The cerebral bioelectrical activity and blood flow indicators were recorded in the pool of the common carotid and vertebral arteries. Results . In the main group and the clinical comparison group, the rheographic index and the peripheral vascular resistance index were studied, which characterize both the volume pulse blood filling of the vascular bed and the tone of small and medium caliber arteries. At the same time, the EEG rhythm indices were analyzed: а -, в -, S-, and в -waves. An analysis of the intersystem interaction of bloodflow indices and the biopotentials of the cortical rhythm of the brain in the main group showed a mismatch in the intra-system connections, which corresponds to the period of the general stress of the body. An analysis of the correlation between the indicators of electroencephalography and rheoencepha-lography in the control group revealed a stable system of correlation between the indicators, showing intersystem and intrasystem consistency and reflecting a high level of reserve capacity of the body and the state of steady adaptation to adverse factors. Conclusion . The use of simultaneous recording of cerebral hemodynamics and brain biopotentials in patients with osteochondrosis of the cervical spine will allow clinicians to correctly assess the functional state of the central nervous system and to prescribe adequate treatment in a timely manner.

Every patient in neurocritical care evolves through two phases. Acute pathologies are addressed first. These include trauma, hemorrhagic or ischemic stroke, or neuroinfection. Soon after, the concentration shifts to identifying secondary pathologies like fever, seizures, and ischemia, which may exacerbate the brain injury. Frequent bedside examinations are not sufficient for timely detection and prevention of secondary brain injury (SBI) as per the International Multidisciplinary Consensus Conference on Multimodality Monitoring in Neurocritical Care. Multimodality monitoring (MMM) can help in tailoring treatment decisions to prevent such a brain injury. Multimodal neuromonitoring involves data-guided therapeutic interventions by employing various tools and data integration to understand brain physiology. Monitors provide real-time information on cerebral hemodynamics, oxygenation, metabolism, and electrophysiology. The monitors may be invasive/noninvasive and global/regional. We have reviewed such technologies in this write-up. Novel themes like bioinformatics, clinical research, and device development will also be discussed. How to cite this article Ruhatiya RS, Adukia SA, Manjunath RB, Maheshwarappa HM. Current Status and Recommendations in Multimodal Neuromonitoring. Indian J Crit Care Med 2020;24(5):353–360.

This study examined the effects of ego depletion on challenge and threat states and cerebral hemodynamic responses to a pressurized muscular endurance task requiring self-control. Following the ethical approval, 58 participants (39 male, 19 female; M age = 28 years, SD = 12) were randomly assigned to either an experimental or a control group. Participants then completed self-report measures of trait anxiety and self-control. Next, the experimental group performed a written transcription task requiring self-control, whereas the control group transcribed the text normally. Finally, before the pressurized muscular endurance task, challenge and threat states were assessed using demand and resource evaluations and cardiovascular reactivity, whereas cerebral perfusion in the frontopolar region (Fp1 and Fp2) was assessed using nearinfrared spectroscopy. The results supported the effectiveness of the self-control manipulation, with the experimental group transcribing fewer words, making more errors, and regulating their writing habits more than the control group. Although there were no differences between the groups in terms of muscular endurance performance or challenge and threat states, there was a significant interaction of Time (Pre vs. Post) × Group (Experimental vs. Control) in cerebral perfusion. These findings suggest that ego-depletion might not influence challenge and threat states but may lead to reduced cerebral perfusion. As such, cerebral perfusion may be a novel marker that could be used to assess ego depletion.

Introduction: Low cerebral blood flow can affect cognition in patients with high-grade asymptomatic internal carotid artery stenosis. Current clinical algorithms use stroke risk to determine which patients should undergo revascularization without considering cognitive decline. Although correlations between low-flow and cognitive impairment have been reported, it is not known whether a threshold exists below which such a correlation expresses itself. Such information would be critical in treatment decisions about whether to intervene in patients with high-grade carotid artery stenosis who are at risk for cognitive decline. Objective: To determine how reduced blood flow correlates with lower cognitive scores. Methods: Patients with ≥80% unilateral internal carotid artery stenosis with no history of stroke were recruited from inpatient and outpatient practices at a single, large, comprehensive stroke center. Patients underwent bilateral insonation of middle cerebral arteries with standard 2-Hz probes over the temporal windows with transcranial Doppler. Cognitive assessments were performed by an experienced neuropsychologist using a cognitive battery comprising 14 standardized tests with normative samples grouped by age. Z-scores were generated for each test and averaged to obtain a composite Z-score for each patient. Multivariable linear regression examined associations between mean flow velocity (MFV) and composite Z-score, adjusting for age, education, and depression. The Davies test was used to determine if there was a breakpoint for a non-zero difference in slope of a segmented relationship over the range of composite Z-score values. Results: Forty-two patients with unilateral high-grade internal carotid artery stenosis without stroke were enrolled (26 males, age = 74 ± 9 years, education = 16 ± 3 years). Average composite Z-score was –0.31 SD below the age-specific normative mean (range –2.8 to +1.2 SD). In linear regression adjusted for age, education, and depression, MFV correlated with cognitive Z-score (β = 0.308, p = 0.043). A single breakpoint in the range of composite Z-scores was identified at 45 cm/s. For MFV 45 cm/s, Z-score change was nonsignificant (95% CI: –0.07 to 0.05). Conclusions: In high-grade, asymptomatic carotid artery stenosis, cognitive impairment correlated linearly with lower flow in the hemisphere fed by the occluded internal carotid artery, but only below a threshold of MFV = 45 cm/s. Identifying a hemodynamic threshold for cognitive decline using a simple, noninvasive method may influence revascularization decision-making in otherwise “asymptomatic” carotid disease.

Background and objectives In our previous proof-of-principle study, transcranial photobiomodulation (tPBM) with 1,064-nm laser was reported to significantly increase concentration changes of oxygenated hemoglobin (∆[HbO]) and oxidized-state cytochrome c oxidase (∆[oxi-CCO]) in the human brain. This paper further investigated (i) its validity in two different subsets of young human subjects at two study sites over a period of 3 years and (ii) age-related effects of tPBM by comparing sham-controlled increases of ∆[HbO] and ∆[oxi-CCO] between young and older adults. Study design/materials and methods We measured sham-controlled ∆[HbO] and ∆[oxi-CCO] using broadband near-infrared spectroscopy (bb-NIRS) in 15 young (26.7 ± 2.7 years of age) and 5 older (68.2 ± 4.8 years of age) healthy normal subjects before, during, and after right-forehead tPBM/sham stimulation with 1,064-nm laser. Student t tests were used to test statistical differences in tPBM-induced ∆[HbO] and ∆[oxi-CCO] (i) between the 15 young subjects and those of 11 reported previously and (ii) between the two age groups measured in this study. Results Statistical analysis showed that no significant difference existed in ∆[HbO] and ∆[oxi-CCO] during and post tPBM between the two subsets of young subjects at two study sites over a period of 3 years. Furthermore, the two age groups showed statistically identical net increases in sham-controlled ∆[HbO] and ∆[oxi-CCO]. Conclusions This study provided strong evidence to validate/confirm our previous findings that tPBM with 1,064-nm laser enables to increase cerebral ∆[HbO] and ∆[oxi-CCO] in the human brain, as measured by bb-NIRS. Overall, it demonstrated the robust reproducibility of tPBM being able to improve cerebral hemodynamics and metabolism of the human brain in vivo in both young and older adults. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

Background: High altitude sojourn challenges blood flow regulation in the brain, which may contribute to cognitive dysfunction. Neurovascular coupling (NVC) describes the ability to increase blood flow to working regions of the brain. Effects of high altitude on NVC in frontal regions undergoing cognitive activation are unclear but may be relevant to executive function in high-altitude hypoxia. This study sought to examine the effect of incremental ascent to very high altitude on NVC by measuring anterior cerebral artery (ACA) and middle cerebral artery (MCA) hemodynamic responses to sustained cognitive activity. Materials and Methods: Eight adults (23 ± 7 years, four female) underwent bilateral measurement of ACA and MCA mean velocity and pulsatility index (PI) through transcranial Doppler during a 3-minute Stroop task at 1400, 3440, and 4240 m. Results: Resting MCA and ACA PI decreased with high-altitude hypoxia (p

RationaleDisturbances in dynamic cerebral autoregulation after ischemic stroke may have important implications for prognosis. Recent meta-analyses have been hampered by heterogeneity and small samples.Aim and/or hypothesisThe aim of study is to undertake an individual patient data meta-analysis (IPD-MA) of dynamic cerebral autoregulation changes post-ischemic stroke and to determine a predictive model for outcome in ischemic stroke using information combined from dynamic cerebral autoregulation, clinical history, and neuroimaging.Sample size estimatesTo detect a change of 2% between categories in modified Rankin scale requires a sample size of ∼1500 patients with moderate to severe stroke, and a change of 1 in autoregulation index requires a sample size of 45 healthy individuals (powered at 80%, α = 0.05). Pooled estimates of mean and standard deviation derived from this study will be used to inform sample size calculations for adequately powered future dynamic cerebral autoregulation studies in ischemic stroke.Methods and designThis is an IPD-MA as part of an international, multi-center collaboration (INFOMATAS) with three phases. Firstly, univariate analyses will be constructed for primary (modified Rankin scale) and secondary outcomes, with key co-variates and dynamic cerebral autoregulation parameters. Participants clustering from within studies will be accounted for with random effects. Secondly, dynamic cerebral autoregulation variables will be validated for diagnostic and prognostic accuracy in ischemic stroke using summary receiver operating characteristic curve analysis. Finally, the prognostic accuracy will be determined for four different models combining clinical history, neuroimaging, and dynamic cerebral autoregulation parameters.Study outcome(s)The outcomes for this study are to determine the relationship between clinical outcome, dynamic cerebral autoregulation changes, and baseline patient demographics, to determine the diagnostic and prognostic accuracy of dynamic cerebral autoregulation parameters, and to develop a prognostic model using dynamic cerebral autoregulation in ischemic stroke.DiscussionThis is the first international collaboration to use IPD-MA to determine prognostic models of dynamic cerebral autoregulation for patients with ischemic stroke.

Purpose: The parameters of cerebral blood flow are modulated by many factors. The aim of the study was to prospectively assess the relationship between the number of the established cardiovascular ...

Continuous-flow left ventricular assist devices (LVADs) reduce peak systolic flow, increase diastolic flow, and eliminate pulsatility of circulation. Altered blood flow may lead to a change in end-organ perfusion. Analysis of the flow dynamics of the arteries of end organs, such as the brain, may indicate whether an organ is perfused sufficiently. The aim of this study is to evaluate and identify the flow pattern changes of carotid (CA) and middle cerebral arteries (MCA) in LVAD patients and to compare with heart failure patients and healthy volunteers. Eighty-nine individuals were included in this cross-sectional study. Participants were divided into three groups: LVAD patients (n = 31), heart failure patients (n = 26), and healthy volunteers (n = 27). Carotid and transcranial Doppler ultrasonography were performed for all study groups for peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility (PI), and resistive (RI) indices of CA and MCA. Flow dynamics were compared between the groups. Doppler ultrasonographic data were analyzed at a median 12 (3-47) months after LVAD implantation. CA-PSV was lower in LVAD group compared with the other two groups (P

The aim of this study was to evaluate the effects of the carotid artery stenting (CAS) procedure on cerebral hemodynamics and cognitive performance in patients with internal carotid artery stenosis. In this prospective observational study, 16 consecutive patients in a single institute were treated with CAS from 2010 to 2011 (71.7 ± 7.3 years old, 12 males, and six left-sided procedures). Before and after the CAS procedure, all patients were evaluated with single photon emission computed tomography usingsup123/supI-iodoamphetamine and acetazolamide as well as the Weschler Adult Intelligent Scale (WAIS) to assess three intelligent quotients and four indexes. Patients with decreased preprocedural cerebral blood flow (CBF) and cerebrovascular reserve (CVR) experienced significant increases in CBF and CVR (P = 0.01 and 0.03). Twelve (75%) patients experienced a significant increase in one or more WAIS scores, while two (13%) showed a significant decrease. The most frequently improved scores were the Working Memory Index and Processing Speed Index (seven patients/44%). Preprocedural CBF was significantly correlated with the Full-scale and Performance Intelligent Quotients (r = 0.51-0.56, P = 0.02-0.04), and patients who experienced a significant increase in these scores had larger increases in CVR than patients with unchanged scores (P = 0.0097-0.019). These results indicate that the CAS procedure improved impaired cerebral hemodynamics and might benefit the cognitive function of patients with internal carotid artery stenosis related to impaired cerebral hemodynamics.

Ischemic stroke is one of the most common cerebrovascular diseases and is the leading cause of disability all over the world. It is well known that cerebral blood flow (CBF) is disturbed or even disrupted when ischemic stroke happens. The imbalance between demand and shortage of blood supply makes ischemic stroke take place or worsen. The search for treatments that can preserve CBF, especially during the acute phase of ischemic stroke, has become a research hotspot. Animal and clinical experiments have proven that remote ischemic conditioning (RIC) is a beneficial therapeutic strategy for the treatment of ischemic stroke. However, the mechanism by which RIC affects CBF has not been fully understood. This review aims to discuss several possible mechanisms of RIC on the cerebral hemodynamics in ischemic stroke, such as the improvement of cardiac function and collateral circulation of cerebral vessels, the protection of neurovascular units, the formation of gas molecules, the effect on the function of vascular endothelial cells and the nervous system. RIC has the potential to become a therapeutic treatment to improve CBF in ischemic stroke. Future studies are needed to highlight our understanding of RIC as well as accelerate its clinical translation.

Exposure to moderate hypoxia in humans leads to cerebral lactate production, which occurs even when the cerebral metabolic rate of oxygen (CMRO2) is unaffected. We searched for the mechanism of this lactate production by testing the hypothesis of upregulation of cerebral glycolysis mediated by hypoxic sensing. Describing the pathways counteracting brain hypoxia could help us understand brain diseases associated with hypoxia. A total of 65 subjects participated in this study: 30 subjects were exposed to poikilocapnic hypoxia, 14 were exposed to isocapnic hypoxia, and 21 were exposed to carbon monoxide (CO). Using this setup, we examined whether lactate production reacts to an overall reduction in arterial oxygen concentration or solely to reduced arterial oxygen partial pressure. We measured cerebral blood flow (CBF), CMRO2, and lactate concentrations by magnetic resonance imaging and spectroscopy. CBF increased (P 0.076) in all groups, as expected. Lactate increased in groups inhaling hypoxic air (poikilocapnic hypoxia: $0.0136\ \frac{\mathrm{mmol}/\mathrm{L}}{\Delta{\mathrm{S}}_{\mathrm{a}}{\mathrm{O}}_2}$, P Lactate production was not associated with reduced CMRO2. These results point toward a mechanism of lactate production by upregulation of glycolysis mediated by sensing a reduced arterial oxygen pressure. The released lactate may act as a signaling molecule engaged in vasodilation.

Transcranial Doppler (TCD) and transcranial color-coded duplex sonography (TCCS) are valuable real-time neurologic monitoring tools in the ICU. Pulsatility index (PI) is one of the most important hemodynamic parameters provided by TCD/TCCS, which allows one to assess the cerebral hemodynamic changes in a patient with acute neurological injury. Here, we focus on the clinical utility of PI to guide clinical management.

Subarachnoid hemorrhage is a devastating disease with high morbidity and mortality and multiple neurological and systemic complications. Delayed cerebral ischemia due to vasospasm is the most frequent neurological complication, and related symptoms may develop in up to 30% of cases.

Cardiac arrest is a leading cause of mortality and morbidity. The prognosis of patients that survive to intensive care unit admission largely depends on the severity of the neurological injury. Prevention of secondary brain injury is the mainstay of treatment in the intensive care unit. This chapter describes the temporal course of the cerebral perfusion and autoregulation of post-cardiac arrest patients during treatment in the intensive care unit. Knowledge of the cerebral pathophysiological processes after cardiac arrest is essential for adequate treatment of these patients.

In this chapter, we will discuss the utility of transcranial Doppler to assess cerebral hemodynamics and how to apply it to understand the cerebral blood flow changes in acute brain injury. First, we will start by reviewing important cerebral hemodynamics principles such as cerebrovascular resistance, adequate cerebral blood flow, and cerebral autoregulation. We will finalize this chapter by assessing the interpretation of transcranial Doppler in aneurysmal subarachnoid hemorrhage, intracranial hypertension, and impending brain death.